Joint assembly with centering flange

ABSTRACT

The present invention provides a joint assembly for operatively coupling rotating parts. The joint assembly comprises first and second joint members. A plurality of torque-transmitting balls are secured in a cage disposed between the joint members. The second joint member is disposed about an axis and includes a centering flange having a first length for mounting to the second rotating part. The centering flange has a contact section configured for being in a substantially interference fit with the second rotating part. The contact section has a second length substantially smaller than the first length of the centering flange such that the substantially interference fit provides proper alignment between the centering flange and the second rotating part while minimizing forces necessary to mount the centering flange to the second rotating part.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to and all the benefits of U.S. provisional patent application Ser. No. 60/654,323, filed Feb. 18, 2005, hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to joint assemblies for operatively coupling rotating parts. More specifically, the present invention relates to joint assemblies comprising multiple joint members with one of the joint members having a centering flange for mounting to one of the rotating parts.

2. Description of Related Art

Joint assemblies for operatively coupling first and second rotating parts are well known in the art. One particularly well known joint assembly is referred to as a constant velocity or CV joint. A typical CV joint comprises a first joint member for mounting to a first rotating part and a second joint member for mounting to a second rotating part. A plurality of torque-transmitting elements, usually in the form of torque-transmitting balls, are disposed between the first and second joint members to operatively couple the first and second joint members. The first joint member can be fixed to the first rotating part in any number of fashions, such as by splined fits and the like. The second joint member often includes a centering flange for mating with the second rotating part.

Referring to FIG. 1, one such centering flange 10 is shown. Here, the centering flange 10 has an overall length L₁. The centering flange 10 also has a contact section 14 configured for being in a substantially interference fit with an inner cylindrical surface 16 of the second rotating part 18. The contact section 14 has a second length L₂ that extends a substantial portion of the overall length L₁. Since the contact section 14 is in a substantially interference fit with the inner cylindrical surface 16 of the second rotating part 18, the volume of material in the contact section 14 must be displaced when mounting the centering flange 10 to the second rotating part 18, either by forces deflecting the centering flange 10 radially inwardly or by forces deforming the centering flange 10. The larger the volume of material to be displaced, the larger the force required to mount the centering flange 10 to the second rotating part 18, and likewise, the larger the force required to remove the second rotating part 18 to repair or replace the joint assembly. Furthermore, this prior art centering flange, which is cylindrical so as to present a straight pilot, requires a precision fit and is susceptible to binding.

Therefore, there is a need in the art for a centering flange that has a contact section configured in a way such that the substantially interference fit between the centering flange and the second rotating part provides alignment between the centering flange and the second rotating part while minimizing the forces necessary to mount the centering flange to the second rotating part.

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention provides a joint assembly for operatively coupling first and second rotating parts. The joint assembly comprises a first joint member for mounting to the first rotating part and a second joint member for mounting to the second rotating part. The second joint member is disposed about an axis and includes a centering flange having a first length for mounting to the second rotating part. At least one torque-transmitting element is disposed between the first and second joint members for operatively coupling the first and second joint members. The centering flange has a contact section configured for being in a substantially interference fit with the second rotating part when mounting the centering flange to the second rotating part. The contact section has a second length substantially smaller than the first length of the centering flange such that the substantially interference fit between the centering flange and the second rotating part provides alignment between the centering flange and the second rotating part while minimizing forces necessary to mount the centering flange to the second rotating part.

By making the length of the contact section substantially smaller than the overall length of the centering flange, the substantially interference fit requires displacement of less material than the prior art centering flange shown in FIG. 1 with the same outer dimensions. As a result, tolerances between the centering flange and the second rotating part can be increased. In other words, variations in dimensions of the centering flange of the present invention can be higher than the prior art centering flange since the contact section of the centering flange of the present invention is much smaller than that of the prior art centering flange.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a partial cross-sectional view of a prior art centering flange of a joint assembly;

FIG. 2 is a cross-sectional view of a joint assembly of the present invention;

FIG. 3 is a elevational view of the joint assembly of the present invention;

FIG. 4 is a partial cross-sectional view of the centering flange of the present invention in assembly with a rotating part; and

FIGS. 5-14 are cross-sectional views of various embodiments of the centering flange of the joint assembly of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a joint assembly for coupling first 20 and second 22 rotating parts is shown generally at 24. In one embodiment, the joint assembly 24 is described as a constant velocity, or CV joint. However, the joint assembly 24 may be any joint assembly capable of operatively coupling parts for rotation, while allowing the parts to deviate from perfect axial alignment with one another.

Referring to FIGS. 2-3, the joint assembly 24 includes a first joint member 26, known as an inner race in some embodiments, for mounting to the first rotating part 20. The joint assembly 24 also includes a second joint member 28, known as an outer race in some embodiments, for mounting to the second rotating part 22. The first joint member 26 is formed with an outer curved surface 30 (see FIG. 3) in which a plurality of first ball grooves 32 are formed. The second joint member 28 has an open end 34 in which the first joint member 26 is disposed, an opposite closed end 36, and an inner curved surface 38 in which a plurality of second ball grooves 40 are formed.

At least one torque-transmitting element 44 is disposed between the first 26 and second 28 joint members to operatively couple the first 26 and second 28 joint members. The at least one torque-transmitting element 44 is further defined as a plurality of torque-transmitting balls 44 arranged in pairs of the first 32 and second 40 ball grooves between the first 26 and second 28 joint members. A cage 46 contains and secures the plurality of balls 44 between the first 26 and second 28 joint members. The balls 44 transmit torque between the joint members 26, 28. The first 26 and second 28 joint members, the cage 46, and the balls 44 may be formed of any material capable of transferring torque between the first 20 and second 22 rotating parts including ferrous and non-ferrous metals, and the like.

Preferably, the first joint member 26 includes an opening 48 with splines for fitting onto mating splines of the first rotating part 20. It should be appreciated by those skilled in the art that the first rotating part 20 may be a stub shaft, e.g., forming part of a drive shaft, with the joint assembly 24 being utilized to transmit rotational energy, e.g., torque, from the drive shaft to the second rotating part 22 wherein the second rotating part 22 may be an output shaft for extending to a transfer case, an input shaft of a differential, or the like.

A boot 54 is mounted onto the second joint member 28 and is arranged to be fitted onto the first rotating part 20 to retain lubrication within the joint assembly 24 as the first rotating part 20 rotates inside the boot 54. The boot 54 may comprise any suitable material that is sufficiently flexible to allow the joint assembly 24 to operate through a wide range of angles such as thermoplastic and elastomeric materials.

Referring to FIG. 4, the second joint member 28 is formed with a radial mounting flange 56 adjacent the closed end 36. The radial mounting flange 56 is adapted to be bolted to a mating flange 58 of the second rotating part 22. The mating flange 58 has a shoulder 62 with a cylindrical inner surface 64 of predetermined diameter centered about a second axis 66 of the second rotating part 22.

The second joint member 28 further includes an annular pilot projection or centering flange 68 disposed about an axis 70 of the second joint member 28 and extending axially toward the second rotating part 22. The centering flange 68 is dimensioned for a substantially interference fit with the cylindrical inner surface 64 in order to center the second joint member 28 on the second rotating part 22 with the axes 66, 70 aligned and in position for the radial mounting flange 56 of the second joint member 28 to be bolted to the mating flange 58 of the second rotating part 22. It should be appreciated that the substantially interference fit refers to the overall fit between the centering flange 68 and the cylindrical inner surface 64 while also including imperfections in the shapes of the centering flange 68 and the cylindrical inner surface 64 that may result in portions not being in an interference fit with one another. The centering flange 68 is preferably fixed to the second joint member 28, and more preferably is integrally formed with the second joint member 28.

Referring to FIG. 5, the centering flange 68 is formed with a profiled outer surface 72 that enables the centering flange 68 to be slid into engagement with the cylindrical inner surface 64 of the shoulder 62, while the axes 66, 70 are misaligned (i.e., with the second joint member 28 slightly cocked relative to the second rotating part 22) without causing the second joint member 28 to bind at the centering flange 68 after one of a plurality of bolts (not shown) has been tightened. In one embodiment, shown in FIG. 5 for instance, the outer surface 72 is convexly curved in the axial direction in order to provide contact with the cylindrical inner surface 64 of the shoulder 62.

To better understand the fit between the centering flange 68 and the inner cylindrical surface 64 of the shoulder 62, the geometry and dimensioning of the centering flange 68 is described. The centering flange 68 is disposed about the axis 70 of the second joint member 28 and has a first length L₁. The first length L₁ is considered the overall axial length of the centering flange 68 relative to the axis 70 of the second joint member 28.

The centering flange 68 has a contact section 76 configured for being in the substantially interference fit with the inner cylindrical surface 64 of the shoulder 62 of the mating flange 58 when mounting the centering flange 68 to the inner cylindrical surface 64. The contact section 76 has a second length L₂ substantially smaller than the first length L₁ of the centering flange 68 such that the substantially interference fit between the centering flange 68 and the inner cylindrical surface 64 provides alignment of the axes 70 between the centering flange 68 and the second rotating part 22 while minimizing forces necessary to mount the centering flange 68 to the second rotating part 22.

In one embodiment, the term substantially smaller is further defined as the second length L₂ being less than 70 percent of the first length L₁. In a further embodiment, the term substantially smaller is further defined as the second length L₂ being less than 50 percent of the first length L₁. In yet another embodiment, the term substantially smaller is further defined as the second length L₂ being less than 30 percent of the first length L₁.

The centering flange 68 also includes at least one non-contact section 80 configured for not being in a substantially interference fit with the inner cylindrical surface 64 of the shoulder 62. The non-contact section 80 radially extends from the axis 70 of the second joint member 28 at a first maximum radius R₁ and the contact section 76 radially extends from the axis 70 at a second maximum radius R₂ greater than the first maximum radius R₁. As a result, the contact section 76 extends further radially outwardly than the non-contact section 80 to provide the substantially interference fit between the contact section 76 and the inner cylindrical surface 64.

The outer surface 72 may comprise any of a number of shapes in cross-sectional profile that will provide a contact section 76 for being in the substantially interference fit with the inner cylindrical surface 64 while minimizing the forces necessary to mount the centering flange 68 to the second rotating part 22 and accommodating misalignment during connection of the second joint member 28 with the second rotating part 22. In other words, various shapes of the outer surface 72 are contemplated by the present invention. Some of these shapes are shown in FIGS. 5-14.

In FIGS. 5 and 6, the outer surface 72 is further defined as a curved surface. The curved surface of FIG. 5 is formed at a single radius R₃, while the curved surface of FIG. 6 is formed at multiple radii R₄, R₅.

In FIGS. 7 and 8, the outer surface 72 is further defined as a plurality of joined frustoconical surfaces. In FIG. 7, first and second frustoconical surfaces are arranged such that a base of the first frustoconical surface includes the contact section 76, while the second frustoconical surface includes the non-contact section 80. In FIG. 8, the contact section 76 is partially defined at the intersection of two frustoconical surfaces.

In FIG. 9, the outer surface 72 is further defined as a semi-elliptical surface.

In FIG. 10, the outer surface 72 is further defined as a parabolic surface.

In FIG. 11, the outer surface 72 is further defined as a plurality of frustoconical surfaces joined by a cylindrical surface.

In FIG. 12, the outer surface 72 includes a projection or protrusion extending radially outwardly relative to the axis 70 of the second joint member 28. The protrusion includes the contact section 76, while the non-contact section 80 lies on both sides of the protrusion.

In FIG. 13, the outer surface 72 is further defined as a curved surface as in FIGS. 5 and 6, except that the curved surface is formed at a single radius R6 with an offset. In this embodiment, the offset is in the non-contact section 80.

In FIG. 14, the outer surface 72 is further defined as a plurality of frustoconical surfaces joined by a curved surface.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims. 

1. A joint assembly for coupling first and second rotating parts, comprising; a first joint member for mounting to the first rotating part, a second joint member including a centering flange having a first length disposed about an axis for mounting to the second rotating part, and at least one torque-transmitting element disposed between said first and second joint members for operatively coupling said first and second joint members, said centering flange having a contact section configured for being in a substantially interference fit with the second rotating part when mounting said centering flange to the second rotating part wherein said contact section has a second length substantially smaller than said first length of said centering flange such that the substantially interference fit between said centering flange and the second rotating part provides alignment between said centering flange and the second rotating part while minimizing forces necessary to mount said centering flange to the second rotating part.
 2. A joint assembly as set forth in claim 1 wherein said second length is less than 70 percent of said first length.
 3. A joint assembly as set forth in claim 2 wherein said second length is less than 50 percent of said first length.
 4. A joint assembly as set forth in claim 3 wherein said second length is less than 30 percent of said first length.
 5. A joint assembly as set forth in claim 1 wherein said centering flange has at least one non-contact section configured for not being in a substantially interference fit with the second rotating part wherein said at least one non-contact section radially extends from said axis at a first maximum radius and said contact section radially extends from said axis at a second maximum radius greater than said first maximum radius.
 6. A joint assembly as set forth in claim 1 wherein said centering flange includes an outer surface.
 7. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a curved surface.
 8. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a plurality of joined frustoconical surfaces.
 9. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a semi-elliptical surface.
 10. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a parabolic surface.
 11. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a plurality of frustoconical surfaces joined by a cylindrical surface in relation to said axis of said second joint member.
 12. A joint assembly as set forth in claim 6 wherein said outer surface includes a protrusion extending radially outwardly relative to said axis of said second joint member.
 13. A joint assembly as set forth in claim 6 wherein said outer surface is further defined as a plurality of frustoconical surfaces joined by a curved surface.
 14. A joint assembly as set forth in claim 1 wherein said second joint member is further defined as an outer race.
 15. A joint assembly as set forth in claim 14 wherein said centering flange is integrally formed with said outer race.
 16. A joint assembly as set forth in claim 14 wherein said first joint member is further defined as an inner race.
 17. A joint assembly as set forth in claim 16 wherein said inner race includes an opening having splines for fitting onto the first rotating part.
 18. A joint assembly as set forth in claim 17 wherein said at least one torque-transmitting element is further defined as a plurality of torque-transmitting balls.
 19. A joint assembly as set forth in claim 18 including a cage securing said plurality of torque-transmitting balls between said inner race and said outer race. 